The present invention relates to a robotics-based, automated object-handling device. More particularly, it relates to a continuous motion device incorporating multiple, coaxially arranged robotic arms.
Automated object handling equipment is utilized in countless industrial applications. For example, automated processing equipment is useful for product or component construction, assembly, packaging, inspection, etc. In this regard, automated processing equipment can assume a wide variety of forms, but are generally categorized in one of two distinct classes. The first class of automated processing equipment is high-speed dedicated machinery characterized by continuous motion mechanisms, such as a rotating turntable, that allows the machinery to operate smoothly at high speeds. A second class, generally referred to as robotics, utilizes a reciprocating, computer controlled robotic arm to perform certain operations. Both classes of automated machinery have certain advantages and drawbacks. For example, dedicated machinery is typically less complex, and is able to process a much larger volume of components through various stations as compared to robotic machinery due to the continuous motion design. Conversely, robotic machinery is typically able to perform more complex motions, and can more readily be reconfigured or programmed for different work environments/handling requirements.
Efforts have been made to improve upon the effective speeds of robotic machinery. For example, U.S. Pat. No. 5,042,774 describes coaxially mounting two robotic arms. While providing enhanced operational capabilities, the arms are not capable of rotating 360°, and therefore cannot provide a more preferred, continuous motion. Conversely, other references, such as U.S. Pat. Nos. 5,678,980, 5,789,878, and 6,102,164 describe a semiconductor wafer-transferring device including two commonly linked robotic arms secured to a central hub. While effectuating a continuous motion feature, the so-described robotic arms are limited to two degrees of freedom, and operate in different planes. As a result, while satisfying specific constraints associated with semiconductor wafer processing, the described robotic assemblies have minimal usefulness for other manufacturing scenarios. Further, only two articles can be handled at any one time. Other continuous motion robotic arm designs are similarly limiting.
A multitude of design obstacles have contributed to the inability to perfect a continuous motion, multiple robotic arm system. First, it is not enough to simply stack two or more robotic arms on top of one another. In addition to the obvious complications associated with driving such a system, the arms are manipulated out-of-plane relative to one another, thereby limiting the potential manufacturing applications. Second, to optimize overall efficiency, it is greatly preferred that more than two robotic arms be provided with a single device. Once again, this constraint has heretofore presented insurmountable obstacles in devising an appropriate, and cost-effective, drive system. Third, for enhanced arm manipulation, it is preferred that each robotic arm be provided with three degrees of freedom. While single arm, three degree of freedom robots are well known, existing drive systems for these robotic devices are not amenable to a continuous motion, multi-arm device. Fourth, the availability of desired arms paths by coupling or uncoupling the various arms lengths has not been explored. Fifth, the system is preferably highly flexible. That is to say, an optimal continuous motion robotic system affords the user the ability to quickly and easily alter a portion of the system such that the resulting arm paths satisfy the requirements of different handling applications. These constraints in combination with industry's willingness to accept the drawbacks associated with dedicated machinery and robotic devices, have likely hindered design efforts into a continuous motion robotic handling device.
Material handling systems or machinery continue to evolve. Unfortunately, however, a system optimally combining the attributes of high-speed dedicated machinery and flexible or robotic machinery is currently unavailable. Therefore, a need exists for a continuous motion robotic device providing multiple robotic arms that is useful for a wide variety of different processing applications.